commit 2ff85183b959c05134a2737d6d14afd1882f2ba3
author Jim Raykowski <raykowj@gmail.com> Wed Apr 26 17:16:20 2023 -0800
committer Tomaž Vajngerl <quikee@gmail.com> Thu Apr 27 07:36:30 2023 +0200
tree dfed46a57ae2df641b46ac44977e17bcce856362
parent 0340cbbc34d2c97baa5b7ebc4a57650861907067

tdf#38194 Use a hashed string HSL color approach

for style name color creation

New magic for style name color creation.

Change-Id: Ia6eec2dcf04fc2c3c38276bf6eaed73598505947
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/151079
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

sfx2/source/dialog/StyleList.cxx

diff --git a/sfx2/source/dialog/StyleList.cxx b/sfx2/source/dialog/StyleList.cxx
index ce2d2f9..7b17137 100644
--- a/sfx2/source/dialog/StyleList.cxx
+++ b/sfx2/source/dialog/StyleList.cxx
@@ -63,6 +63,7 @@
#include <StyleList.hxx>

#include <vcl/virdev.hxx>
#include <basegfx/color/bcolortools.hxx>

using namespace css;
using namespace css::beans;
@@ -94,42 +95,21 @@ public:

namespace
{
Color ColorHash(const OUString& rString)
Color ColorHash(std::u16string_view rString)
{
    // method 1
    //Color aColor(rString.hashCode() & 0xFFFFFF);
    static std::vector aSaturationArray{ 0.90, 0.75, 0.60 };
    static std::vector aLightnessArray = aSaturationArray;

    // method 2 borrowed from https://github.com/RolandR/ColorHash/blob/master/colorhash.js
    //sal_Int32 nSum = 0;
    sal_uInt32 nStringHash = OUString(rString).hashCode();

    //for (int i = 0; i < rString.getLength(); i++)
    //{
    //    nSum += rString[i];
    //}
    double nHue = nStringHash % 359;
    double nSaturation = aSaturationArray[nStringHash / 360 % aSaturationArray.size()];
    double nLightness
        = aLightnessArray[nStringHash / 360 / aSaturationArray.size() % aLightnessArray.size()];

    //sal_uInt8 nRed = OUString("0." + OUString(OUString::number(std::sin(nSum + 1))).copy(6)).toDouble() * 256;
    //sal_uInt8 nGreen = OUString("0." + OUString(OUString::number(std::sin(nSum + 2))).copy(6)).toDouble() * 256;
    //sal_uInt8 nBlue = OUString("0." + OUString(OUString::number(std::sin(nSum + 3))).copy(6)).toDouble() * 256;
    basegfx::BColor aHSLColor(nHue, nSaturation, nLightness);

    //Color aColor(nRed, nGreen, nBlue);

    // method 3 std::hash
    //const std::hash<OUString> hasher;
    //Color aColor(hasher(rString) & 0xFFFFFF);

    // method 4
    sal_uInt32 nLen = rString.getLength();
    sal_uInt32 nHashCode = nLen;
    while (nLen > 0)
    {
        nHashCode = (nHashCode * 107) + rString[nLen - 1];
        nLen--;
    }
    sal_uInt32 nColor = nHashCode & 0xFFFFFF;
    Color aColor(ColorTransparency, nColor);
    aColor.ApplyTintOrShade(5000);

    return aColor;
    return Color(basegfx::utils::hsl2rgb(aHSLColor));
}

// used to disallow the default character style in the styles highlighter character styles color map